Means for scraping off wooden surfaces



DeC- 23, 1930- A s. THIELMANN 1,786,096

MEANS FOR SCRAPING OFF WOODEN SURFACES iled March 30. 1929 e @Off u Illu-l llill Patented Dec. 23. 1930 UNITED STATES 'PATENT OFFICE SEBASTIAN THIELMANN, OF BERLIN, GERMANY, ASSIGNOR TO NOIAN U ELEK- TRISCHE APPARATE G. I. B. H., AOF BERLIN-HALENSEI, GERIANY, A CORPORATION OF GERMANY MEANS FOR SCRAPIN G OFF WOODEN SUBFACES Application iled- Hatch 30, 1929, Serial No. 351,298, and in Germany September 1, 19.28.

My invention relates to a new means for scraping oil' inlaid iloors or similar wooden surfaces. To scrape oli' Such floors or Surfaces so-called scraper ribbons are used which either are mounted on a suitable base plate or on a cylinder adapted to revolve rapidly. These scraper ribbons either pos- Sess individual scrapers liattened out on their front faces and bentI in known manner, or wire bails arranged in staggered relation to one another, the middle portion or web of which is flattened out or sharpened.

In both these cases the individual Scrapers or scraping bails are mounted by their ends ona ribbon consisting of felt or rubber and fitted with a linen cloth stiiening and are held thereon by their free ends being bent over on the rearside of the ribbon, the mounting of the scra ers being carried out in known manner y means of suitable setting machines. Although these scraper ribbons are manufactured mechanically and have turned out to be well Suited for the purpose aimed at, their use is comparatively expensive, asin particular the life of the Scrapers, when consisting of bail-Sha ed wires, is comparatively short, the web o the bail wearing out very rapidly by its repeatedly being resharpened. Besides, the mounting of the scraper ribbon on a motor-driven rotary cylinder involves certain diiculties due to the helical course of the ribbon.

Now my invention has for its object to obviate these drawbacks. I likewise employ wire bails thev middle portion or web of which is sharpened and forms the scraping ymember proper, but according to my invention no individual wire bails are mounted on a felt Ior rubber ribbon, but the 'scra ers form a continuous organic whole extendlng when y mounted for use, along a helical line and having polygonal cross section. The lateral legs of the continuous scraping member thus obtained may be bent at the middle, instead of in the customary way, near one end, soV that the member may be turned 180-v degrees on the cylinder and the opposite webs of the individual polygonal Spires be used as Scrapers.

In order that my invention may be more easily understood, two preferred embodiments of the same are illustrated by way of example in the accompanying drawings as well as a motor-driven scraping machine fitted with my new scraping member. In these drawings Figure 1 is a fra entary side view of my new scraping mem er,

Figure 2 is a corresponding top view,

Figure 3 is a lateral view of the other embodiment of the member,

Figure 4 is one of the individual Scrapers the member is composed of, in an enlarged lateral view, to better show its sharpened scraping edge,

Figure 5 is a side view of a scraping machine fitted with the new scraping member v and driven by an electric motor,

vFigure 6iS a corresponding top view, and

Figure 7 is a section,`on an enlarged scale, through the cylinder having mounted on it 'the scraping member.

Referring first to Figures 1 and 2, the continuous wire which forms the individual Scrapers constitutes a member of rectangular cross section and consisting of individual bails the legsof which are denoted by a, b, while the upper middle portion or web is denoted by o; d is the lower connecting Section which normally Serves as supporting member. The le S a, b are bent at a suitable level, at e, a out 45 degnees, as can be seen rom Figures 1 andfl. After having mounted the described wire member along a spiral line on the cylinder, the outer bail portions or webs c are sharpened, in the manner to be seen from Fi re 4, by means of a suitable grinding mac ne, so as to form scraping edges c1 suitable to scrape the inlaid ioor or similar wooden surface. When the edges have become dull, they can easily be re-Sharpened.

In the embodiment illustrated in Fi 3, the legs a, b are bent about in the mi dle, so that the spiral wire member may be turned over after the webs chave become dull, so that the lower webs d, now the outer ones,can be sharpened and serve as Scrapers.

AIn the embodiment shown the wire is assumed to have circular cross section. As a l' polygonal cross section, in particular a flat band-like cross section, in order to obtain a more favorable scraping eiect.

The operative portions of the member, that is the webs c or d are hardened, as usual in such Scrapers, to increase their resistance, unless the whole spiral member consists of a hard material, e. g. piano string wire.

The described Wire member is mounted along a spiral line on a Wooden cylinder f illustrated in Figures 5 to 7 and fastened thereon by means of a metal ribbon g drawn therethrough. This ribbon g is secured in position on the cylinder f by pins projecting from the cylinder and engaging corresponding holes in the ribbon, the ends of the latter being fixed on the cylinder f, b any suitable means. The cylinder is provi ed with trunnions i, Which are slid, for instance, into the slotted bearing ends k of the fork-shaped frame m of the machine and secured therein by cotters n. The cylinder f is driven in a known manner by an electric motor r through the intermediary of a suitable gear train s. In the scraping operation the cylinder f rests on the surface to be treated.

What I claim, is

1. A scraping device consisting of a plurality of polygonal loops of Wire joined together in 4the form of a helix, said loops having their sides along at least one side of said helix provided with a scraping edge.

2. A scraping device consisting of a frame, a substantially cylindrical drum rotatably mounted upon said frame, a' plurality of loops of wire joined together in the' form of a helix helically Wound around said drum, said loops having sharpened flat outer sides lying in a virtual cylinder coaxial with said drum, and means for rotating said drum.

The foregoing specification signed at Berlin this 14th day of March, 1929.

SEBASTIAN THIELMANN. 

